BearWorks MSU Graduate Theses Summer 2015 Design of High Temperature Evaporator for Spectroscopic Study of Equilibrated Vapor Phase Materials Yarden Bosch As with any intellectual project, the content and views expressed in this thesis may be considered objectionable by some readers. However, this student-scholar’s work has been judged to have academic value by the student’s thesis committee members trained in the discipline. The content and views expressed in this thesis are those of the student-scholar and are not endorsed by Missouri State University, its Graduate College, or its employees. Follow this and additional works at: https://bearworks.missouristate.edu/theses Part of the Materials Science and Engineering Commons Recommended Citation Bosch, Yarden, "Design of High Temperature Evaporator for Spectroscopic Study of Equilibrated Vapor Phase Materials" (2015). 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DESIGN OF HIGH TEMPERATURE EVAPORATOR FOR SPECTROSCOPIC STUDY OF EQUILIBRATED VAPOR PHASE MATERIALS A Masters Thesis Presented to The Graduate College of Missouri State University In Partial Fulfillment Of the Requirements for the Degree Master of Science, Materials Science By Yarden Bosch July 2015 DESIGN OF HIGH TEMPERATURE EVAPORATOR FOR SPECTROSCOPIC STUDY OF EQUILIBRATED VAPOR PHASE MATERIALS Physics, Astronomy, & Materials Science Missouri State University, July 2015 Master of Science Yarden Bosch ABSTRACT This work details the design, assembly, and testing of a high temperature electron beam evaporator for equilibrated vapor phase evaporation of rock oxides for the purpose of astrophysical characterization of extrasolar planetary atmospheres. Infrared spectroscopy of high temperature SiO2 atmosphere created through the electron beam evaporation technique and trapped by argon ice matrix isolation was performed to generate a reference spectrum against which absorption lines in stellar spectra taken during planetary transits can be compared. Studies demonstrate that water inclusions in milky quartz (SiO2) can be used to create H2O/SiO2 equilibrated atmospheres within a Knudsen cell. Modeling of exoplanet spectra can be used to determine spectral photometry results as seen by astronomers for comparison with reference spectra collected. KEYWORDS: exoplanet, hot super-earth, FTIR, electron beam evaporation, modeling This abstract is approved as to form and content _______________________________ Dr. David Cornelison Chairperson, Advisory Committee Missouri State University ii DESIGN OF HIGH TEMPERATURE EVAPORATOR FOR SPECTROSCOPIC STUDY OF EQUILIBRATED VAPOR PHASE MATERIALS By Yarden Bosch A Masters Thesis Submitted to the Graduate College Of Missouri State University In Partial Fulfillment of the Requirements For the Degree of Master of Science, Materials Science July 2015 Approved: _______________________________________ David Cornelison _______________________________________ Mike Reed _______________________________________ Peter Plavchan _______________________________________ Julie Masterson, PhD: Dean, Graduate College iii TABLE OF CONTENTS Introduction ..........................................................................................................................1 Extra-Solar Planets...................................................................................................1 Atmospheres ............................................................................................................3 Knudsen Cell Theory ...............................................................................................9 Observational Work ...............................................................................................13 Engineering ........................................................................................................................23 High Temperature Evaporation Overview .............................................................23 High Temperature Evaporator Design ...................................................................30 Testing of High Temperature Evaporator ..............................................................35 High Temperature Evaporation of Water ..............................................................39 Results ...............................................................................................................................40 Evaporator ..............................................................................................................40 Water Inclusion at High Temperatures ..................................................................50 High Temperature Measurement of SiO2 ..............................................................52 Spectral Modeling for Astrophysical Interest ........................................................55 Future Work ...........................................................................................................63 References ..........................................................................................................................65 Appendices ........................................................................................................................67 App. A: MATLAB Simulation Code .....................................................................67 App. B: MATLAB Spectral Analysis Code ..........................................................81 App. C: Additional Research .................................................................................82 iv LIST OF TABLES Table 1. Known super-Earth planets and their surface temperatures. .................................3 Table 2. Elemental composition of komatiites used for kinetic chemistry simulations in codes such as MAGMA .......................................................................................................7 Table 3. Hot super-Earth planetary candidates found by the Kepler mission .....................8 v LIST OF FIGURES Figure 1. Hot super-Earths relative to all Kepler planetary candidates ...............................1 Figure 2. Artist’s depiction of Kepler 10b ...........................................................................2 Figure 3. Atmospheric gas composition relative to surface temperature for a planet with Earth’s composition, calculated using MAGMA.................................................................4 Figure 4. Model of CoRoT-7b’s internal structure ..............................................................5 Figure 5. Atmospheric gas composition for CoRoT-7b assuming 2500 K temperature and 10-2 bar pressure for two alternate compositions, calculated using MAGMA ....................6 Figure 6. Partial pressures for atmospheric gases for a komatiite composition ...................9 Figure 7. Simplified representation of a Knudsen cell ......................................................10 Figure 8. A channel orifice allows fewer molecules to escape than a knife-edge orifice ..11 Figure 9. Distribution of molecules for a thin orifice and a channel orifice, derived from Monte Carlo simulation .....................................................................................................12 Figure 10. Planetary phases indicating detectable reflected light ......................................14 Figure 11. Planetary transit of Kepler 10b .........................................................................14 Figure 12. Spectrum of sunlight compared with sunlight that has passed through Earth’s atmosphere .........................................................................................................................15 Figure 13. Example of the use of photometry to attempt to fit to model compositions for the hot Jupiter type exoplanet WASP 12b .........................................................................16 Figure 14. Path of spectrometer beam ...............................................................................17 Figure 15. Diagram of an interferometer used for FTIR spectroscopy..............................18 Figure 16. Example interferogram and Fourier transform spectrum .................................19 Figure 17. Resistively heated Knudsen cell designs incorporating Ta heating elements, heat shields, and water cooling ..................................................................................................26 Figure 18. Feedthrough pins used to isolate cathode from scaffolding .............................31 vi Figure 19. Top and side views of hot cathode filament design and completed filament ...32 Figure 20. Side, top, and bottom views of evaporation crucible .......................................33 Figure 21. Side and top views of evaporation crucible lid ................................................34 Figure 22. Circuit diagram of electron beam evaporator ...................................................35 Figure 23. Vacuum chamber used for testing of high temperature electron beam evaporator ............................................................................................................................................36 Figure 24. A proposed future chamber design which simplifies in-situ spectroscopy